A conventional laser printer utilizes a rotating drum coated in an organic photoconductor (OPC) material that can be electrically discharged by exposure to light. A charge roller applies a voltage, for example negative 600 Volts, to the surface of the OPC drum. A laser diode generates laser pulses according to a pixel map of the image to be printed, and a rotating polygon mirror causes the laser pulses to be scanned across a surface of the OPC drum, thereby electrically discharging portions of the OPC drum. Charged toner particles are exposed to the OPC drum and thus attracted to those portions of the OPC drum that remain charged. A piece of paper passes between the rotating drum and a positively charged transfer roller. The toner on the drum is pulled and thereby deposited on portions of the paper. A fuser melts the toner onto the paper creating a permanent image. Conventional printing utilizes wood pulp-based paper. Although paper can be recycled, the paper-based printing paradigm may not be sustainable going forward.
Electronic reader devices have become common in recent years. The reading surfaces of such devices include tiny cells of electronic ink. The electronic ink includes charged colored particles suspended in a fluid, and selective application of a voltage differential across the reading surface causes the charged colored particles to rise to the surface, thereby creating a visible image. Useful and popular though they are, electronic reader devices are not a perfect substitute for paper.